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Columbia research suggests need to rethink causes of heart failure

13.04.2005

Research at NYPH/Allen pavilion shows more than half of patients may be affected by factors external to heart

New research from Columbia University Medical Center is challenging the traditional explanation for the causes of the most common type of heart failure, traditionally called diastolic heart failure. The study of 145 patients at NewYork-Presbyterian Hospital/The Allen Pavilion suggests that the most common type of heart failure is caused by health problems outside the heart.

The study, published in the April issue of the Journal of Cardiac Failure, suggests the majority of heart failure cases might be better treated with drugs to target specific disorders that are causing the heart failure - e.g. anemia, obesity, hypertension and diabetes - rather than the treatments currently prescribed specifically for heart failure.

Heart failure is the currently the number one reason for hospital admission in patients over the age of 65. With the growing elderly population this condition is expected to increase exponentially. Current estimates are that of the more than 5 million people in the United States with heart failure, more than half have heart failure despite the heart having normal pumping function.

"Our data suggests that the classic definition of heart failure fails to take into account the wide range of health problems that can be associated with the disease," said Mathew S. Maurer, M.D., Irving Assistant Professor of Medicine at Columbia University College of Physicians and Surgeons and Director of the Clinical Cardiovascular Research Laboratory for the Elderly at the NewYork Presbyterian Hospital/The Allen Pavilion, who was the studys principal investigator. "A broader view of heart failure is necessary to understand its causes and treat these patients."

Heart failure patients have been routinely classified into one of two groups - those with hearts that are pumping abnormally, considered systolic heart failure, and those with hearts that pump blood out normally but have trouble filling with blood, which was typically called diastolic heart failure.

The patients who were the subject of the study have heart failure but normal ejection fractions – the measurement of the hearts ability to pump blood. It was previously believed that heart failure patients with a normal ejection fraction had small, thick-walled hearts that made it exceedingly difficult for them to fill with enough blood. The Columbia study showed, however, that many patients with heart failure and normal ejection fractions had hearts that were bigger than average.

Unique 3-D Imaging System Allows Unprecedented Accuracy

Previous studies failed to account for the shape of the heart, but a one-of-a-kind three-dimensional imaging system developed by Columbia University Medical Centers Donald King, professor emeritus of radiology, provided an accurate measurement of heart shape. The other studies just measured heart width, but Dr. Kings 3-D echocardiography system also measured heart length, proving that these patients did not have smaller hearts, as previously believed.

Prior to this study researcher had also compared the cardiac failure patients hearts to a standardized heart size similar to that of a healthy 25 year old, rather than taking into account that this disease predominantly affects elderly women, who have smaller hearts.

"By accurately measuring patient heart size and comparing it to the hearts of healthy elderly women, we showed for the first time that not only were the heart failure hearts not smaller, but in many cases they were larger, meaning we need to look elsewhere to discover the roots of this problem," said Dr. Maurer.

The Columbia researchers measured left ventricular end-systolic and end-diastolic volumes in 35 heart failure patients with normal ejection fractions and hypertension, as well as 11 patients with heart failure and no high blood pressure and 99 asymptomatic normal controls. While all of the subjects had normal pumping function of the heart, the subjects with heart failure and a normal ejection fraction and low blood pressure had trouble filling their small to normal sized hearts, and wall thickening that was out of proportion to their ventricular volume. However, for the majority of elderly subjects with heart failure and a normal ejection with concomitant hypertension, there was a concomitant increase in ventricular volume and mass, suggesting that the ventricle had no difficulty filling.

According to Dr. Maurer, the heart may not be the proximate cause of the syndrome, but rather it could be responding to conditions outside heart failure in patients with normal ejection fractions.

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